Less Manganese lost over 1050 0 C Manganese in Sea Water Excessive Background signal from NaCL Large loss of analyte.

Use only INSTRUMENT GRADE Acetylene (99.5% or better).

Acetylene cylinders must not be used at pressures below 500 kPa. Doing so mayallow acetone to enter the fuel line and damage the instrument.

Do NOT use oxygen or oxygen-enriched air.

Heat, vapours and fumes generated by the flame can be toxic, hazardous to yourhealth.

Switch on the exhaust before lighting the flame.

NEVER use glass bottles for waste. Use only plastic beakers or containers.

Never aspirate organics with a density <0.75 g/mL as a flashback may result.

Never bring acetylene in direct contact with Cu, Ag, Hg, Cl or grease as an explosionmight result.

Compressed gases should always be handled with care andin strict accordance with the gas manufacturersinstructions.

Keep gas cylinders cool and secured to the well in an uprightposition with a thick chain.

The acetylene line pressure must not exceed 100 kPa as thegas may spontaneously explode.

If gases are allowed to escape into the laboratory, anexplosion or suffocation may occur. Check all gas lines forgas leaks, and ensure proper ventilation in the laboratory.

Do not use a flame for gas leak testing but use a weak soapsolution such as "Snoop".

Never pass acetylene through copper, brass or tubing wherethere is a greater than 65% copper as an explosion mayresult.

Less Manganese lost over 10500C

Manganese in Sea Water

Excessive Background signal from NaCL

Large loss of analyte

separates the analyte element from the chemical matrix– eliminates matrix interference effects

– minimises background absorption

improves efficiency of atomisation for certain elements over conventional FAAS– ppm to ppb/ppt levels of detection

hydride forming elements– As, Bi, Pb, Sb, Se, Sn & Te

mercury– CVAAS / amalgamation

Spectral very rare in the gas phaseKinetic

caused by varying rates of development / liberation of the hydrideincomplete digestion of samples - high organic contentfoam production can retard hydride productionadd anti-foaming agent n-octanol / Dow Corning AntifoamBpeak area integration eliminates most effects

Oxidation state only AAS technique which is oxidation state sensitivehigher sensitivity is obtained for the lower oxidation state

Group 5A elements - As, Sb & Bi+3 oxidation state +5 oxidation state (<2x signal decrease)

Group 6A elements - Se & Te+4 oxidation state only gives signal

Pre-reduction necessaryGroup 5A elements - KI/Ascorbic acid or KI/strong acidGroup 6A elements - hot 4-6M HCltreat standards as samples

Chemical most mineral acids at high concentration will only slightly depress signalHCl, HNO3 & H2SO4 used for sample/standard preparationHF & HClO4 remaining from digestion must be dilutedpeak area integration can eliminate most effectsmajor interferences from Group 8 elements (Fe, Co, Ni, Ru, Rh, Pd, Os, Ir, Pt) or Group 1B elements (Cu, Ag & Au)increase acid concentrationadd complexing agentadd masking agents (Fe in presence of Ni)well documented

Gas phase mutual interaction between analyte & competing element‘competing’ for hydrogen free radicalshydrides with other hydridesdepends on speed of hydrides reactingadd KIadd ions that interfere with interferent - Cu(II) with Se/Aswell documented

Systematic Hg contamination - soak/clean all glassware & tubing with HNO3 + waterHg adsorption (to surface of vessels) minimised by acidifying to pH2.5purity of reagents & acidsvolatilisation during sample preparation

closed vessel digestion

•Slowly liberate Hg vapour from system•Hg is collected by amalgam formation on gold ribbon in system•gold ribbon rapidly heated to 500-700oC•concentrated Hg vapour released gives higher signal•ppt levels of detection possible

inject samplesmoothly dry sampleash / char sample to remove sample matrixefficiently atomise analyteclean tube before next sample injection

sample volume deposited on base of tubeinjection depth

volume dependant 10-40 Lsample dependant

rate of injectionobserve using dental mirror

dry temperature based on solventvolume dependantinitial dry step just less than b.p of sample second dry step just above b.p of sampleslow ramp used between stepsmax inert gas flow used (3L/min)observe using dental mirror

rapidly generate as many free ground state atoms as possibleGBC recommend atomise temperatures - methods manualatomise hold time will vary with analyte - 1 to 2s ‘read’rapid atomise heating rate - 1000oC to 2000oC/sensure whole signal is capturedinert gas stop used (0L/min)2s gas stop recommended before atomise step

rapidly generate as many free ground state atoms as possibleGBC recommend atomise temperatures - methods manualatomise hold time will vary with analyte - 1 to 2s ‘read’rapid atomise heating rate - 1000oC to 2000oC/sensure whole signal is capturedinert gas stop used (0L/min)2s gas stop recommended before atomise step